Ask the experts! Help No. 2
 

... what rhymes with gorilla ... is owned by the State of NH... is pretty much an unimproved mess of a boat launch, dirt ramp?

Long Island Inn
 

The spot off Long Island is owned by the Austin family. The road in the picture ( now a grass path) leads to the still standing and now on the state register of historic places Long Island In. From the Moultonboro Historical Society:
Long Island Inn in 1874, with the steamboat landing known as “Brown’s Wharf” just below the Inn on the western shore of the lake. The boulders which composed the wharf are still in place and can be seen from the lake today. The “Mount Washington” and the “Lady of the Lake” were
among the steamboats which delivered guests and mail with five daily stops. Another was the “Lamprey”, earlier known as the “Montclair”, which was built on the beach on the southeast part of the island. The hotel, based on the Brown’s original farmhouse, was operated by George K. Brown, son of
John and Catherine, and later by George’s son, Harry. Barbara and Will Austin now have it as a bed and breakfast. It once was able to accommodate 50 guests.

I don't know the date, but when the bridge to Long Island was built, the ferry became obsolete.

The side wheeler burned in 1939. In the early 40's MW II gave her engines to the war effort, so I'd suggest regular stops at the landing ended before 1940. Wood or coal fired steamers may have continued, but we don't hear much about the war years.